Tensioning apparatus



April 1932- F. c. BIGGERT, JR

' TENSIONING APPARATUS Filed March 14, 1931 WITNESSES I j CIgVVEhfTOR Patented Apr. 12, 1932 PATENT OFFICE FLORENCE C. IBIGGERT, JR., OF GRAFTON, PENNSYLVANIA, ASSIGNOR TO UNITED ENGINEERING & FOUNDRY COMPANY,

PORATION OF PENNSYLVANIA OF PITTSBURGH, PENNSYLVANIA, A COR- TENSIONING- APPARATUS Application filed March 14, 1931. Serial No. 522,764.

The invention relates to the cold rolling of strip metal, and has particularly to do with apparatus for applying tension to such metal as it emerges from the pass of a pair of rolls,

the term strip being herein used in its broad sense as defining long fiat plates and sheets of metal regardless of what width they may be.

In the cold rolling of sheet metal, the prevailing practice is to apply tension to strip as it emerges from a single stand of rolls, or from the last stand of a continuous mill, the effects of which tensioning are to maintain the strip flat, to facilitate its alignment in the roll pass, and to improve its physical properties. Usually suchtension is applled by a reel upon which'the strip is wound.

Because of the prevailing high speed of rolling, and the diificulty attending the engaging of the leading end of a strip by a reel,

it is necessary to place the reel at a material distance from a roll stand. Consequent- 1y, substantial lengths of both the leading N and trailing ends of each strip are not subjected to the same'tensioning as its intermediate portion, and accordingly are not as flat, and do not have the same physical properties, as the intermediate portion. The unstressed leading-end portion is longer than the trailing-end portion because tension is not applied, or fully so, to the strip until its leading end has been wrapped around a reel.)

Both of the unstressed ends of a strip are later cut from the intermediate portion, and either scrapped or sold as a lower grade product than the intermediate portion.

The object of this invention is to provide a tensioning apparatus for the purpose explained, which apparatus may be placed close to the delivery side of. a roll pass,

which quickly engages'the leading end of a strip regardless of the speed of rolling, and which effectively applies a desired tension to the strip without marring its surface and without pressure reduction of its thickness.

In the accompanying drawings. Fig. l is a perspective view of a strip tensioning apparatus embodying my invention, shown in association with a stand of rolls; and Fig. 2 a diagrammatic illustration of an electric system for controlling the operation of the tensioning apparatus.

The strip tensioning apparatus provided according to'this invention comprises a plurality of pairs of pinch rolls arranged in tandem close to each other to simultaneously engage a strip and cumulatively apply tension to it as it passes between them. Preferably, each pair of the pinch rolls is so driven that it independently applies to the strip an increment of the desired tension. While each pair of the tensioning rolls may have a single drive, it is preferred to drive each roll of each pair independently.

Referring to the drawings, the invention is illustrated as comprising a plurality of pairs ot pinch rolls 1, 2 and 3, the number of which may be varied depending upon the requirements of service. These are suitably mounted in a simple compact fashion in a single frame or housing 4, and the complete structure positioned relatively close to the mill with which they are used, as for example the four-high mill schematically indicated by working rolls 5 backed by rolls 6.

For varying the relative positions of the associated pairs of pinch rolls, to adapt them for operation upon different thicknesses of strip, and for varying the pressure with which they grip the strip, screw downs 7 are arranged in the top of framev 4 at points opposite the ends of each pair of the rolls. For

' driving each of the rolls individually, a plurality of motors 8, 9, 11, 12, 13 and 14 are suitably coupled directly to the rolls, al-

though any other suitable form of drive or coupling may be used. Wabbler connections such as the wabbler shown in United States Patent No. 691,294 or the like are, of course, provided between motors 8, 9 and 11 and rolls 1, 2 and 3 to allow for the adjustment of these rolls by screws 7 without interference with the drive of the rolls. The details of such construction are so well known in the art that it has not been deemed necessary to show them here in detail.

To simplify the construction and assembly of the apparatus, the motors 8, 9 and 11 which are coupled to the upper of the different pairs of pinch rolls are mounted on a shelf or proas to place the motors mounted upon them in alignment with the rolls to which they are attached.

the pair of pinch rolls So that all of the difi'erent pairs ot-pinch rolls may operate cumulatively upon the stock, each successive pair may be so driven as to give, or tend to give it a slightly greater peripheral speed than the preceding pair. While various forms of controls known to the art may be used for this purpose, a suitable system is that shown in Fig. 2, wherein the roll motors areyeach connected to a source of current supply 18 through individual current tension regulators 21, 22, 23, 24:, 25 and 26. respectively. The construction and method of operation of regulators of this character are so well known in the art that it is deemed unnecessary to illustrate or describe them here in detail. 7,

By using the tensioning apparatus provided according to my invention, it is unnecessary to use reels for tensioning strip, or even for reeling it. If it is desired to coil the strip, this may be done by a simple type of blocker, including a group of strip-bending rolls 19 and coil-supporting rolls 2(), which suitably coil the strip in the loose form advantageous for subsequent use or treatment.

In operation, the regulators are adjusted to automatically vary the speed of each motor in such a way as to cause the diflerent rolls to assume and maintain the respective loads which they are intended to carry. Consequently, when a strip 17 enters the tensioning apparatus, the motors 8 and 12 coupled to 1 automatically adjust themselves to cause those rolls to develop and maintain a given or pre-selected tensional forcein the strip. In a similar fashion, the motors 9 and 13, and 11 and 14 coupled to the pairs of rolls 2 and 3, respectively, adjust themselves to assume their load when the strip is engaged by them. Consequently,-a total tension is cumulatively imparted to the strip by the various pairs of rolls, which tension is equal substantially to the sum of the forces exerted upon the strip by each of the pairs. Also, each pair 1s prevented by reason of such control from assuming more than its own load and at the same time is caused to maintain the load which it is set to carry. If for any reason any pair of them attempt at any time to exceed its intended load, or to relieve another pair of its load, the regulators, associated with the motors of the pair of rolls affected, automatically react to correct such conditions.

As previously explained, the tensioning apparatus is arranged close to the delivery side of a pair of rolls so that the leading end of 'a delivered strip is quickly and easily engaged by the successive pairs of pinch rolls. By thus cumulatively applying tension 'to the strip, there is no liability of the pinch rolls slipping upon the faces of the strip and prejudicially burnishing it, and no liability of the thickness of the strip being reduced by pressure exerted upon it by tensioning rolls, as would happen in case a single palr of pinch rolls were used to apply substantial tension to strip. Because the tensioning apparatus may be placed close to the delivery side of a rolling mill, the untensioned leading and trailing ends of strip are much shorter than those which result from the tensioning of strip by reels. Accordingly, materially larger portions of each strip may be sold or used as first quality material.

According to the provisions of the patent statutes, 1 have explained the principle an operation of my invention, and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically shown and described.

I claim:

1. Apparatus for tensioning strip metal as it emerges from the delivery side of a rolling mill, comprising a plurality of pairs of pinch rolls arranged intandem to simultaneously engage a strip and apply tension to it' as it passes through them, and individual means for driving each of said pairs of pinch rolls to cumulatively exert a tension upon the strip equal substantially to the sum of the forces imparted to it by each of the separate pairs of rolls individually.

2. Apparatus for tensioning strip metal as it emerges from the delivery side of a roll-.

and means for controlling the operation of each of said driving means in such a way as v to cause the several pairs of pinch rolls to collectively exert a tensioning force upon the strip equal substantial!y to the sum of the forces imparted to it by each of the several pairs of rolls individually.

3. Apparatus for tensioning strip metal as it emerges from the delivery side of a rolling mill, comprising a plurality of pairs of pinch rolls arranged to operate simultaneously upon a strip passed betweenthem, and individual driving means operably coupled to each of said rolls for driving each roll independently of every other roll.

4:. Apparatus for tensioning strip metal as it emerges from the delivery side of a rolling mill, comprising a plurality of pairs of pinch rolls arranged to operate in tandem to simultaneously en- 3 upon a strip of material passed between them, and means for driving each roll of each of said pairs of rolls individually and in such a way that the total force imparted to the strip by them collectively equals substantially the sum of the forces imparted thereto by each of the pairs of rolls.

In testimony whereof I sign my name.

FLORENCE BIGGERT, JR. 

